﻿////////////////////////////////////////////////////////////////////////////////////////////////////
//
// VSCoverageToEmma - Visual Studio Coverage file to Emma converter
// Copyright (c) Kouji Matsui, All rights reserved.
//
// * Redistribution and use in source and binary forms, with or without modification,
//   are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
////////////////////////////////////////////////////////////////////////////////////////////////////

using System;
using System.Collections.Generic;
using System.Linq;

namespace VSCoverageToEmma
{
	public sealed class ArgumentParser
	{
		private readonly Dictionary<string, Action<string>> flags_ =
			new Dictionary<string, Action<string>>(StringComparer.InvariantCultureIgnoreCase);
		private readonly List<Tuple<Action<string>, Action>> handlers_ =
			new List<Tuple<Action<string>, Action>>();

		public ArgumentParser()
		{
		}

		public ArgumentParser AddFlagHandler(string name, Action<string> flagHandler)
		{
			flags_.Add(name, flagHandler);
			return this;
		}

		public ArgumentParser AddHandler(Action<string> handler, Action defaultHandler = null)
		{
			handlers_.Add(Tuple.Create(handler, defaultHandler));
			return this;
		}

		public bool Parse(IEnumerable<string> args)
		{
			var index = 0;
			foreach (var arg in
				from arg in args
				let trim = arg.Trim()
				where trim.Length >= 1
				select trim)
			{
				if (arg.StartsWith("-") || arg.StartsWith("/"))
				{
					var flag = arg.Substring(1);
					Action<string> flagHandler;
					if (flags_.TryGetValue(flag, out flagHandler) == true)
					{
						flagHandler(flag);
					}
					else
					{
						throw new ArgumentException("Unknown flag", flag);
					}
				}
				else if (index < handlers_.Count)
				{
					handlers_[index].Item1(arg);
					index++;
				}
			}

			while (index < handlers_.Count)
			{
				var defaultHandler = handlers_[index].Item2;
				if (defaultHandler == null)
				{
					return false;
				}

				defaultHandler();
				index++;
			}

			return true;
		}
	}
}
